The present invention relates to a hand held dental instrument of the type comprising a handle which is sized for being readily engageable by the dentist, and an elongate blade connected to and extending outwardly from one or both ends the handle.
Instruments of the above type are employed in a number of conventional dental procedures. For example, one instrument of this type, which is commonly referred to as an explorer, comprises a handle and an elongate flexible blade which is composed of stainless steel and which tapers to a sharp point. The dentist holds the instrument in the manner of a pencil and manipulates the point of the blade along the surface of a tooth to check for defects in the enamel caused by cracks, areas of decay, or the like. As will be apparent, a very sharp point is required, since a high degree of sharpness is necessary to provide a "feel" or tactile feedback which the dentist is able to sense and recognize upon encountering a crack or other defect, and to thereby permit an accurate diagnosis of the condition of the tooth. However, conventional stainless steel blades are relatively stiff, which renders the tactile feedback somewhat insensitive, and the point of the stainless steel blade wears relatively quickly, resulting in the need for repeated resharpening operations.
Another dental hand instrument of the described type is referred to as a scaler, which has an arcuate blade of semi-circular or triangular cross-section, and so as to form one or more cutting edges extending along the length direction of the blade. The arcuate configuration of the blade permits it to hug and conform to the exterior surface of a tooth, and when the blade is scraped along the exterior surface of the tooth, it causes removal of tartar and other scale. Here again however, the relative stiffness of the stainless steel from which the blades are made renders the conformance of the blade to the outline of the tooth to be limited, and thus a number of scalers having a variety of configurations are required for each cleaning operation. Also, the stainless steel tends to rapidly wear, causing the cutting edges to be dulled.
Still another dental hand instrument of the described type is referred to as a plugger, which is used during an endodontic root canal procedure to obturate or fill a root canal with gutta percha. In one traditional method of obturating a root canal, strand-like pieces of gutta percha, commonly referred to as "points", are inserted into the previously cleaned root canal. The points are then physically compacted by a plugger, which is inserted into the canal and into contact with the points to compact the points into the canal. Where the apical end of the root canal is severely curved, the plugger is required to flex to a significant degree in order to be able to compact the gutta percha into the apical end. To cause the stainless steel blade to flex to the required degree, it is necessary to impart a significant force to the instrument, and such force in turn causes the instrument to engage and form ledges along the inside wall of the canal. Even more significant however, is the risk that the required axial force may fracture the tooth, which usually requires its subsequent extraction.
A spreader is another dental hand instrument used to obturate root canals, and which is generally similar to a plugger, but which differs from a plugger in that a plugger has a blunt end on the blade whereas a spreader has a pointed end. The spreader thus serves to enter the gutta percha point and compact more in a radial direction, whereas a plugger abuts the upper end of the gutta percha and compacts more in the axial or downward direction. As will be apparent, a spreader also has the danger of ledging the inside wall of the root canal and fracturing the tooth as a result of the required axial force needed to cause it to flex in a curved root canal.
It is accordingly an object of the present invention to provide a dental hand instrument of the described type and which overcomes or at least substantially alleviates the above noted limitations and disadvantages of the known instruments of this type.
It is a more particular object of the present invention to provide a dental explorer which provides significantly more sensitive tactile feedback to the dentist, to thereby permit a more reliable diagnosis of the condition of a tooth.
It is a further object of the present invention to provide a dental scaler which more closely conforms to the exterior surface of a tooth during a cleaning operation, and which is more resistant to wear and dulling of the cutting edges.
It is still another object of the present invention to provide a spreader or plugger for obturating a root canal and which is able to laterally flex under minimal force, so as to permit the instrument to conform to a severely curved root canal without risk of fracturing the tooth.